far as working models may be safely
supposed. Nevertheless, he is believed to have
made a model of something which we in
our days would call a steam-engine; and he
is known to have had a German artisan,
Caspar Kaltoff, in his employ, as model-
maker and machinist. The visitor at
Raglan Castle, in Monmouthshire, is told
of an ingenious mechanical contrivance
with which the Marquis (who was lord of
the castle in the times of the Civil War)
contrived to baffle the Roundheads and
befriend the Royalists on a critical occasion.

The beautiful art of photography is not
so modern, in its leading principles, as
most of us are in the habit of supposing.
It was known nearly a hundred years ago
that certain chemical substances are blackened,
or at least darkened, by exposure to
light; Scheele discovered this fact in
relation to chloride of silver, and Ritter to
nitrate of silver. Sir Humphry Davy, Dr.
Wollaston, and Mr. Wedgwood, actually
obtained photographs in 1802, by taking
advantage of this scientific discovery. A
camera obscura was provided, through
the lens of which the sun's light was
admitted; the light was focalised on a small
sheet of glass painted with a coloured
device or picture; and then it fell upon a
sheet of paper rendered sensitive by nitrate
of silver. It was found that, according to
the depth of colour through which the
light passed, so did the paper become more
or less darkened; reproducing the picture,
not in colours, but with due gradations of
light and shade. In this way, photographs
(as we should now call them) were produced
of patterns, figures, woody fibres of plants,
wings of insects, and delicate designs of
lace. But the affair died out, and was not
revivified for a long series of years; owing
to this fact—that no fixing process had then
been discovered. The photographs darkened
and darkened, day by day, until no
picture of any kind was left. Those clever
men did three-fourths of the work nearly
seventy years ago; but they failed to hit
the remaining fourth; therefore they are
not honoured as the discoverers of
photography.

Not the least noteworthy of these instances
is that which relates to the electric
telegraph. The Jesuit Strada, in 1617,
speculated on the possibility that there might,
some day, be found a species of loadstone
or magnet possessing much more wonderful
properties than those long known.
He supposed it to have such virtues,
"that if two needles be touched with it,
and then balanced on separate pivots, and
the one be turned in a particular direction,
the other will move sympathetically with
it." If, then, two persons were possessed
of two such magnetic needles, and settled
upon a pre-arranged code, they might talk
at any distance. He merely imagined such
a stone, but did not venture to predict
that it would ever be found. The same idea
was developed somewhat more fully by
Henry Van Etten, in 1660, very likely
after reading Strada: "Some say that by
means of a magnet, or such like stone,
persons who are distant from each other
may converse together. For example,
Claude being at Paris, and John at Rome,
if each had a needle touched by a stone of
such virtue, that as one moved itself at
Paris, the other should be moved at Rome;
then let Claude and John have a similar
alphabet, and agree to speak every day at
six o'clock in the evening. Let the needle
make three turns and a half, to signal
that it is Claude, and no other, who
wishes to speak with John. Claude wants
to signify, 'Le roi est à Paris,' and
makes his needle stop at L, then at e,
then at r, o, i, and so of the rest. Now,
at the same time, the needle of John,
agreeing with that of Claude, will go on
moving, and stops at the same letters; so
that he can easily understand or notice
what the other would signify to him."
Van Etten gave a diagram, showing the
dial, needle, pivot, alphabet, &c., for working
out the idea. He was very candid and
honest, however, for he added: "It is a
fine invention; but I do not think there
is a magnet in the world which has such
virtue." And he implied a danger:
"Besides, it is inexpedient, for treasons would
be too frequent, and too much protected."
A pleasant paper in the Spectator gave a
new turn to this idea, pointing out how
two lovers could carry on a sentimental
conversation whenever cruel distance
separated them. Each lover must have a dial,
with the requisite magnet, and all the
letters of the alphabet; but, besides these
letters, it should have "several entire
words which have always a place in
passionate epistles: as flames, darts, die,
language, absence, Cupid, heart, eyes, being,
dear, and the like. This would very much
abridge the lover's pains in the way of
writing a letter, as it would enable him to
express the most useful and significant
word with a simple touch of the needle."
Those who have witnessed the action of
Wheatstone's dial telegraph will perceive